Derivatives of benzanthrone



- No Drawing. App1ication filed December 7, 1928, Serial No. 324,576, and in Germany March 9, 1928.

l atentecl Aug. 11, 1931 UNITED STATES PATENT OFFICE HAFEN-ON-THE-RHINE, AND HANS JOSEF EMIMER', OF MIANNHEIM, GERMANY, AS-

SIGNORS TO GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE- DERIVATIVES 0F IBENZANTHRONE The present invention relates to the production of 2-alkylbenzanthrones.

In our copending application Serlal No.

323,561 for an improvement in the production new condensation products are obtained of the general formula We have now found that these condensation products may be split up by treatment with alkaline saponifying agents such as, for example, aqueous or alcoholic alkalies, according to the following equation:

throne and n-butyric acid are obtained from the condensation product of benzanthrone with di-n-propyl ketone. In many cases it is preferable to carry out in one operation both the preparation of the condensation products, according to our said co-pending application, and the splitting up of the same.

According to the present invention, for example, the industrially important 2- methylbenzanthrone which hitherto could only be obtained from Q-methylanthraquim one, and also hitherto unknown homologues of the same, i. e. benzanthrones substituted in the 2-position by an alkyl group containing more than one carbon atom may be obtained. These homologues may be further substituted in the benza-nthrone ring system as well as in the alkyl group and-are adapted to be used for the preparation of dyestuffs.

The following examples will further illustrate the nature ofthe invention, but the vention is not restricted to these examples. The parts are by weight.

Example 1 A suspension of 10 parts of 2-acetonylbenzanthrone in 200 parts of 10 per centaqueous caustic soda solution is kept boiling forabout 2 hours. After crystallization from benzene the reaction product has a melting point of about 198 C.; it is 2-methylbenzanthrone. is 7 Example 2 A solution of 10 parts of the condensation product obtainable from benzanthrone and acetophenone having a melting point of 205 to 206 6., together with parts of caustic potash in 100 parts of ethyl alcohol is heated to the boiling point until the characteristic greenish blue coloration has disappeared.

i The reaction product which crystallizes out "mister about 3 hours.

. not which crystallizes after cooling has a melting point of about 198 to 200 6.; it is 2methylbenzanthrone.

The benzoic acid which has been split off is present in the mother liquor as the potassium salt.

EmampZe 3 10 parts of acetone are introduced at room temperature in an atmosphere of nitrogen, while stirring, into a mixture of 10 parts of benzanthrone, 20 parts of ground caustic potash, and 40 parts of monochlorbenzene, and the mixture is stirred at the same temper The reaction iture is then diluted with 100 parts of alcohol and is refluxed for about 3 hours. The prodout after cooling is practically pure 2-methylbenzanthrone having a melting point of about 198 to 200 C.

Example 4 A mixture of 10 parts of benzanthrone, 30 parts of ground caustic potash, and 40 parts of anhydrous pyridine is treated at room temperature in an atmosphere of nitrogen, While stirring, with 10 parts of di-npropyl ketone; the stirring is continued at the same temperature for about hours. The blue green reaction mass is poured into ice cold dilute hydrochloric acid, and the brown resin which separates out is dissolved in-100 parts of e per cent alcoholiecaus- This solution 18 heated A suspension oflO parts of 2-acetonylbenzanthrone in a solution which contains 4.0 parts of anhydrous sodium sulfide in 100 parts of ethyl alcohol and 100 parts of water is kept boiling for about 2 hours. The reaction product obtained is Q-methylbenzanthrone identical. with that obtained according to Example 1.

Other weak alkaline agents, such as calcium hydroxid or barium hydroxide in alcoholic aqueous solution, may be used instead of sodium sulfide.

hat V 1. A process for the production of 2-alkylbenzanthrones, which comprises treating a condensation product of a benzanthrone and a ketone corresponding to the general formula:

we claim is z in which R stands for a hydrocarbon radicle which ma an alkyl g agent.

2. The process for the production of 2-propylbenzanthrone, which comprises treating the condensation product of bcnzanthrone and di-n-propyl-lretone corresponding to the formula 3' roup, with an alkaline saponifymg with an alkaline saponifying agent.

3. As a new article of manufacture 2-propylbenzanthrone of the formula:

CHzOH2-C1I crystallizing from glacial acetic acid in long golden yellow needles having a melting point of about 130 to 131. C.

4. A process for the production of 2-alkyl- Y be substitutedand.Bstandsfor benzanthrones, which comprises treating a condensatlon product of a benzanthrone and a ketone correspondlng to the general formula:

R- HOOR in which R stands for hydrogen or an alkyl group and R stands for a hydrocarbon radicle which may be substituted, with an alkaline saponifying agent.

5. A process for the production of Q-alkylbenzanthrones, which comprises treating a condensation product of a benzanthrone and a ketone corresponding to the general formula in which R stands for hydrogen or an alkyl group and R stands for a hydrocarbon radicle which may be substituted, with a caustic alkaline saponifying agent.

6. A process for the production of 2-alkylbenzanthrones; which comprises treating a condensation product of a benzanthrone and a ketone corresponding to the general formula:

in which R stands for hydrogen or an alkyl group and R stands for a hydrocarbon radicle which may be substituted, with an alcoholic caustic alkali solution.

7. As new products 2-alkylbenzanthrones corresponding to the general formula:

tion product of a benzanthrone and a ketone of the general formula:

in which R stands for an alkyl group and R stands for a hydrocarbon radicle which may be substituted, with an alkaline saponifying agent.

In testimony whereof we have hereunto set our hands.

ARTHUR LUETTRINGHAUS. HEINRICH N ERESHEIMER. HANS JOSEF EMMER. 

